Sudocrem! Wonderful stuff for my sweet-itchy and sun-sensitive traddie cob. I damp a sponge and apply it to his muzzle and lips area, and round his eyes (carefully) to protect him against the sun and as a skin healer. Also slather it onto heels and legs in the winter to guard against mud fever.
Udder Cream (particularly in the winter), ditto mud fever as above, cheap and cheerful solution. I apply it to my own hands and then wipe my hands across my face to protect against wind & rain. Fantastic item.
Baby lotion and baby wipes: for those stubborn mud-stains. Pack a packet of baby wipes for a show: useful for cleaning boots, dealing with horse-dribble on your best jacket, etc etc.
Lynn Russell Stain Remover and Mane & Tail conditioner. Fantastic stuff, does what it says on the tin. Have used the Mane & Tail conditioner on my own hair too with good effect!
One of those banana-shaped brushes: really handy and perfect for those awkward places like heels. Don't know how I managed without one.
Horseman's One Step: brilliant for dealing with mucky tack, boots etc.
Sanitary Towels!! Yes, honestly, always keep a few in the First Aid kit - MUCH much cheaper than Animalintex if you need to cover a large wound (and sterile as well). Am never without these.